The present application relates to a magnetic tunnel junction (MTJ) containing device and a method of forming the same. More particularly, the present application relates to a MTJ containing device that includes diamond-like carbon laterally adjacent to a bottom electrode.
Magnetoresistive random access memory (MRAM) is a non-volatile random access memory technology in which data is stored by magnetic storage elements. These elements are typically formed from two ferromagnetic plates, each of which can hold a magnetization, separated by a thin dielectric layer, i.e., the tunnel barrier. One of the two plates is a permanent magnetic set to a particular polarity; the other plate's magnetization can be changed to match that of an external field to store memory. Such a configuration is known as a magnetic tunnel junction (MTJ) pillar.
In such MTJ containing devices, the bottom electrode that is connected to the MTJ pillar can be a source of resputtered conductive metal particles that can deposit on a sidewall of the MTJ pillar, especially when an ion beam etching (IBE) process is used to clean the sidewall of the MTJ pillar. If resputtered conductive metal particles deposit on the tunnel barrier material of the MTJ pillar, electrical shorts may arise, which is a common failure mode. This problem is particularly apparent when the critical dimension (CD) of the bottom electrode exceeds that of the MTJ pillar, which is not an unlikely occurrence due to the difficulty in maintaining circularity at small CDs for hole features.
There is thus a need for providing a MTJ containing device that includes a MTJ pillar located on a bottom electrode that has a reduced CD.